Vince Cable's business department has admitted that the scathing report into Royal Bank of Scotland's treatment of small business customers published last month was different to the one the business secretary had received.

The report, which alleges the bailed-out bank had deliberately forced small firms to go bust to enable RBS to make bigger profits, has prompted the City regulator to investigate and has aroused the interest of the Serious Fraud Office.

The business department said the report Cable saw, by his entrepreneur-in-residence Lawrence Tomlinson, had been sent in full to the Financial Conduct Authority and Prudential Regulation Authority, but the version Tomlinson published last month had been "edited" and "amended".

He does not provide the identities of individuals who have complained, and has faced some scrutiny for removing references to Lloyds Banking Group from an earlier version of his report.

In response to written questions by the shadow business secretary, Chuka Umunna, the business department admitted changes had been made – though not, it said, at the behest of ministers.

Responding on behalf of the department, the Conservative MP Matthew Hancock said in a written answer: "Mr Tomlinson's report on the bank's treatment of businesses in distress was sent to the department for business, innovation and skills (BIS) and seen by ministers, special advisers and officials. The report was passed on in full without amendment to the Financial Conduct Authority and the Prudential Regulation Authority for them to consider.

"Mr Tomlinson subsequently decided to publish an edited and amended version of the report. The editorial decisions were made by Mr Tomlinson, who published the report in an individual capacity. The report was not a matter for approval by anyone within BIS," Hancock said.

Tomlinson has previously told the Guardian the vast majority of complaints he received – and turned into case studies for his report – were about RBS and its GRG operation.

"Roughly, in the first report, cases that we distilled down, 20 were RBS and two were Lloyds and one was something else; or it was 20 and three, or something like that," he said.

Tomlinson is based in Leeds and runs a business that builds sports and racing cars and runs and builds care homes.

Lloyds said: "Tomlinson came to us and the examples weren't SMEs and, when we looked, no evidence of any wrongdoing [was found] so he took them out."